The present invention is directed to analog voltage processing. More particularly, the invention provides a system and method for analog voltage processing in a wide voltage range. Merely by way of example, the invention has been applied to dimming control for one or more cold-cathode fluorescent lamps. But it would be recognized that the invention has a much broader range of applicability.
The cold-cathode fluorescent lamp (CCFL) has been widely used to provide backlight for a liquid crystal display (LCD) module. The CCFL often requires a high alternate current (AC) voltage for ignition and normal operation. Such AC voltage can be provided by a CCFL driver system. The CCFL driver system receives a low direct current (DC) voltage and converts the low DC voltage to the high AC voltage.
Additionally, the CCFL driver system often performs dimming control to adjust brightness of the CCFL. The analog signal used for dimming control can be generated by a controller such as a microcontroller. Often, the analog signal has a wide dynamic range from a low voltage level to a high voltage level. For example, the low voltage level is the ground voltage level, and the high voltage level is close to the supply voltage level. Usually the analog signal needs to be processed in order for the CCFL driver system to perform the dimming control. For example, the signal processing needs to be very precise for a wide range of analog voltage, but such precision often is difficult to achieve.
Hence it is highly desirable to improve techniques for analog voltage processing for dimming control of cold-cathode fluorescent lamp.